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Honda unveils next-generation engines at Tokyo show

November 28, 2011

Honda's new 2.4-liter four-cylinder engine could find its way into the redesigned CR-V in 2013.

Honda Motor Co. on Wednesday at the Tokyo motor show unveiled a lineup of four- and six-cylinder engines, as well as a family of continuously variable transmissions, that will reach the market over the next two years.

The Earth Dreams engines have direct injection and double overhead cams. As the Honda vehicle lineup is redesigned, even the base four-cylinder engine will have a twin-cam setup. Some midcycle revisions could get the new engines before a vehicle receives a full redesign, said Keiji Ohtsu, a chief engineer with Honda r&d.

But while current Honda vehicles progress through their life cycles, some base models will retain their single-cam four-bangers as a cost-saving measure. A new V6 will remain single-cam, but gains considerable power.

The specifications for the new Honda engines are:

-- A 3.5-liter V6 with 310 hp and 265 lb-ft of torque. This is 30 more horsepower and 11 more lb-ft than the outgoing 3.5-liter engine in the Acura TL.

-- A 2.4-liter inline-four with 181 hp and 177 lb-ft of torque. This will be the base engine in the redesigned Accord coming next fall and could find its way into the midcycle change for the CR-V in 2013.

-- A 1.8-liter inline-four with 148 hp and 133 lb-ft of torque, which could be installed in the 2013 midcycle change for the Civic.

-- A 1.5-liter inline-four with 127 hp and 111 lb-ft of torque for the Fit, perhaps in time for the midcycle change in 2012.

-- A 1.6-liter turbodiesel engine that has comparable power to a current 2.2-liter diesel, with 220 lb-ft of torque but much better fuel economy.

Ohtsu said the power figures were preliminary and likely understated. Compared with the current four-cylinder engines, the new design will carry at least a 10 percent fuel economy advantage.

New transmissions

In addition, Honda has designed three continuously variable transmissions, one for mid-sized cars such as the Accord, and two for smaller vehicles such as the Civic, Fit and minicars.

Honda is betting big on continuously variable transmission technology and will use it as its base automatic transmission offering across all four-cylinder engines.

Although current CVTs have a “rubber band” feeling similar to a slipping clutch under acceleration, the Honda system has less feeling of slippage, said Hideki Wakamatsu, general manager of Honda r&d.

Also, the engine control software has been remapped so there is less hunting between the engine and CVT for optimal engine revs and transmission ratios during sudden acceleration, Wakamatsu said.

Honda will continue to offer manual transmissions for markets such as Europe that prefer stick shifts. And traditional stepped-gear automatics will be offered for vehicles such as sport sedans and sports cars where more immediate performance impact is needed, Wakamatsu said.

Hybrid advancements

As for hybrid advancements, Honda's upcoming Accord two-mode hybrid, when combined with a four-cylinder engine, will have equivalent power to the Camry Hybrid but better fuel economy than the Camry's combined 41 mpg rating, said Yusuke Hasegawa, senior chief engineer with Honda r&d.

When combined with a V6 engine, the hybrid system will create V8 power and four-cylinder fuel economy. The system can run in EV-only mode, EV-and-gasoline for passing and acceleration, or gasoline-only for highway cruising.

The two-mode hybrid uses a twin-cam profile. But instead of using its VTEC profile for more power, the hybrid version shifts between the Atkinson cycle for leaner-burning of fuel, and the traditional Otto cycle when more power is needed, depending on the torque load on the engine, Hasegawa said.

In EV mode, the Honda plug-in hybrid can travel for as many as 15 miles at speeds up to 62 mph. The plug-in system has a switch that will allow the driver to save EV-mode ability until later in his drive, such as if he commutes from the empty suburbs to the crowded downtown.

Honda also showed an electric all-wheel hybrid drive system that sends power to the outside wheel during cornering, which aids in traction and performance.

When the new 3.5-liter V6 is combined with a seven-speed dual-clutch transmission with an integrated hybrid-electric motor, the torque output between left- and right-side wheels is independently meted to the outside wheel, using the energy from regenerative braking to provide the power boost.